Method of manufacturing resonance bodies especially for musical instruments



March 12, 1929. K. FUHR 1,705,153

METHOD OF MANUFACTURING RESONANCE BODIES ESPECIALLY FOR MUSICALINSTRUIENTS Filed July 6, 1927 F'llg. 4

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Patented Mar. 12, 1929.

UNITED STATES KARL FUHR, OF BIELEFELD, GERMANY.

MIETHOD OF MANUFACTURING RESONANCE BODIES ESPEGIALLZ' FOR- llIU'SICALINSTRUMENTS.

Application filed July 6, 1927, Serial N 203,846, and in Germany May 21,1928.

resonance bi lies, it. i. top a boarda ior violins, the oh- 3 endsounding qualities for all sorts oi tones was regarded as a matter oi le and skill. it was underi 1c peculi: r to a .rcsonanc e hereliore otiinportr cc, and 'dill'erent 4 for l'l'lVCStlQlllIlllg thattone rereezzan'ipl the niate. which has to stood, that n he i i J body a in iclamp or between ti ir'hed by a bow at hung irec a st ng '4 knuckle .i.we

@ 1e dread rant;- e e, that" he plate in 7 1e "zniile and the peculiarone of the wnole plate only can to invel-itigated.

Tie inwention relates to a .n'iethod and a device tor niauuilfacturii'igresonance bodies with '-.'ibration qualities, which can be lixed with ec :tness in advance. This is obtained by stating the peculiar vibrationsand the peculiar tone of the parts in the whole and in (lithe-eat placesat different steps of the manufacturing process. For this purpose bymeans of a sine ll wand which is brought into longitudinal vibrations,the peculiar tone and vibration are he: rd and the reeoectire parts ol'the body accordingly worked out. By the new n'ie'thod resonance bodiesof a high grade 'rl perlcctne 4 can be produced on a technical lint-G oigrez'it e-l lactness for riolins, ci'illos zirindolines, guitars,sounding diaphragins, loud speakers and the like, bee: me not only the)eculiar tone oi a single part oi the instrument, t. the bottom soundboard, butalso the peculiar vibration of any place oi any process can bestated and the said process ac co din iy arranged.

The (133*"0 to? the new method consists oi a small wand, which is placedverticallv on hi therefore in (-uliar owz'i tone, and brought intolongitudiiial ril'n'ations by striking" it lengthwise by a .Q'er weitedwith water. In the respective place, of the resonance body crossvibrations are hereby produced noticeable by a note of a certainhio'hness. This tone is he result oi? the vibral ions oi the resonancebody produced by passing two wetted lingers lengthwise 2 part, which hasto be Worked and restigated in respect to its peong its surface and thebody oi. the small in order to reduce the influence a, last, the glasswand is mad i preilierably .ie six-17o." the no to the o ass *and ischosen accord.-

e resonance F. e.

a :iolin or the violin itself a ss wand of about 1,3 mm. in thickness 2ml it) nun. in c igih would he ader uate; for a cello a, v. wand of 2,25mm. in thickness and illll -lsr-ll nun. in length would be used.

A further lrau'ageous feature of the in volition co in providing the endoi' the i a small ball or cap o't glass,

. 2 showing in an enlarged scale the lowi end of the small glass rand.

The glass wand 1 is taken at 'ts unper end by two wetted with waterfingers 2 imd 3 of one hand, put on the resonance plate 4; in 'he place,which has to be investigated for working", and brought by striking down\\:,H' l; by the n gers into longitudinal vibratiome which proiilucecross vibratir 4 of the plate, The tone produced hereby iiidliatcs, iiithe plate is worked cm'rectly or needs any correction. i

Fig, 2 shows a small glass wand l with a cap 5 .l'ixed to its lower endin order to pr0- tect the body, 1. e. a ready finished and Yarnishedviolin, from scratching.

I claim:

l. A method for niainrl'acturing resonance bodies especially for inusiinstruments. consisting in brin 1; an an wary body in to eentaet withany place of the resoiisince bodv and into loi'igilndinal vibrations byrubbinig; so as to brin l' said place into cross i'ihral ions peculiarto said place, so that the kind of said cross v brations is stated andaccordingly workingsaid place until the desired kind of vibrations isproduced.

10 of said hollow Wand. with respect to the body to be manufacturedbeing the smallest sufficient for setting said body into Vibrations.

4. A device for manufacturing resonance bodies, consisting in a smallwand of hard and elastic material, such as glass and a protecting cap ofsimilar and sn'ieoth material on one end of said wand.

In witness whereof F. aflix my signature.

KARL FUJI-1R.v

